Members of the New York Police Department who spent time at ground zero in 2011 are developing cancer at much higher rates than before the terrorist attack, according to a forthcoming study.

Police Commissioner Raymond Kelly says that city’s police are showing a fivefold increase in all cancers in the the decade since the collapse of the Twin Towers, compared with the six years before. Thyroid cancer, in particular, has shown a tenfold increase, while non-Hodgkin’s lymphoma has increased by 3.5 times.

The full study has not yet been released but the NYPD wanted to publicly discuss the findings in advance to alert its members.